We plan to study central auditory functions in neurological disorders utilizing measures of auditory evoked potentials. A variety of brain potentials will be studied in normal adults, newborn infants, and patients with diseases of the nervous system. The potentials will be recorded from scalp electrodes using computer averaging techniques. The potentials to be studied include, 1) early latency components (less than 10 ms), i.e., brainstem and frequency following potentials; 2) mid-latency components (10-50 ms); 3) long-latency stimulus and event related components (50-500 ms). Measures of latency amplitude, and hemispheric distribution of the evoked potentials will be quantified in patients with diseases affecting the cerebral hemispheres, mid-brain and brainstem. Particular emphasis will be placed on disorders of maturation of the nervous system in newborn infants, disorders of consciousness in adults (coma), and disorders of higher cortical function (dementia). Appropriate animal experiments are planned to define the neuroanatomical basis of the scalp recorded evoked potentials.